Description
Overview
The FASS Adjustable Diesel Fuel System delivers 290 gallons per hour of clean, consistent fuel flow engineered specifically for the 1998.5-2004 Dodge Cummins 5.9L. Part of the FASS ADJ Fuel System Series, this Signature Series-inspired kit is built for high-performance and competition diesel builds, giving you the versatility to dial in fuel pressure exactly where your engine demands it. It ships as a complete kit and is finished in black on a rugged 6061 T-6 Billet Aluminum foundation.
What sets this system apart is its adjustability. The onboard pump uses the same motor found in the FASS Titanium Signature Series systems, and it allows adjustable fuel pressure from 1 to 75 PSI. That range lets you customize fuel delivery for street, race, or competition applications, matching the appetite of demanding Cummins 5.9L combinations rated for serious horsepower.
Key Benefits
To keep fuel pressure stable when it matters most, FASS engineered a built-in boost compensation port. Air pressure drawn from your intake manifold raises fuel pressure under full throttle, so your engine stays fed during the hardest pulls instead of falling flat as boost climbs. This is exactly the kind of behavior high-output diesel engines rely on when they are working at the top of their power band.
The kit includes a Bulkhead fitting and Suction Tube machined from 6061 T-6 Billet Aluminum. The Bulkhead fitting cleverly functions as both a suction tube and return, featuring a 5/8-inch Suction Tube paired with a 1/2-inch Fuel Return Port. This new and improved design over the previous suction tube lets you route your FASS return line directly, cleaning up the installation and improving overall fuel management.
Highlights
- 290 GPH rated flow to support high-performance and competition Cummins builds
- Adjustable fuel pressure from 1-75 PSI for fully customizable fuel delivery
- Built-in boost compensation port raises fuel pressure under full throttle
- Same motor used in the FASS Titanium Signature Series systems
- 6061 T-6 Billet Aluminum Bulkhead fitting with 5/8-inch Suction Tube and 1/2-inch Fuel Return Port
- Sold as a complete kit in a durable black finish
Fitment
This FASS Adjustable Diesel Fuel System is designed for 1998.5-2004 Dodge Cummins 5.9L Truck and SUV applications. As part of the ADJ Fuel System Series, it is aimed at owners chasing repeatable, high-volume fuel delivery for aggressive performance and race-oriented setups.
Whether you are building a dedicated competition truck or upgrading a high-output daily driver, the adjustable pressure range, boost-referenced compensation, and billet aluminum construction give you the control and durability a serious Cummins deserves. Choose this system when you want a proven FASS motor with the flexibility to tune fuel pressure to your exact combination.
